The extraction of oil from underground sources is, in principle, straightforward. A hole is drilled down to an oil-bearing ground stratum and pipework placed in the hole through which oil can be raised to ground surface level. In some oil wells the oil may be under pressure in the oil bearing stratum so it flows to the surface without any assistance, but in many wells assistance may be required either by pumping to draw up the oil or by the injection of water down to the oil-bearing stratum so that oil comes to the surface mixed with the water. The water injected to the oil-bearing stratum may be sea water, and may be heated so that the oil, if viscous, flows more readily. In this case, what comes to the surface will be an oil-water mixture of which the oil content may well be 10% or more
One problem associated with oil extraction in this way is that of the formation of waxes and scale in the pipe through which the oil/water mixture comes to the surface. As pressure is reduced the further up the pipe the mixture rises, the water become super-saturated and precipitates calcium carbonate and other minerals in the form of aragonite, berite, pyrite, and silicates on the surfaces of the production pipeline. Additionally, asphaltenes and paraffin waxes precipitate (as pour point is reached) from the oil content of the mixture again forming on the surfaces of the pipe and gradually reducing the rate of production. In addition, calcium mineral deposits, and bio-fouling, also cause problems in the water injection wells and the high pressure pumping system necessary for water injection, reducing oil production.
It is broadly the object of the present invention to address the aforementioned problem of pipeline blockage by deposition of minerals, waxes and other substances.